import three;
currentprojection=orthographic(1,1,5);
size(200);
triple[][] P={
  {(-1,-1,-0.5), (-1,-0.3,0), (-1,0.3,0), (-1,1,-0.5)},
  {(-0.3,-1,0), (-0.3,-0.3,0.5), (-0.3,0.3,0.5), (-0.3,1,0)},
  {(0.3,-1,0), (0.3,-0.3,0.5), (0.3,0.3,0.5), (0.3,1,0)},
  {(1,-1,-0.5), (1,-0.3,0), (1,0.3,0), (1,1,-0.5)}
};
draw(surface(patch(P,new pen[]{blue,green,red,yellow})));

